Mg II Absorption through Galaxies at Intermediate Redshift Chris Churchill (New Mexico State University) Collaborators: Glenn Kacprzak (NMSU) Chuck Steidel (Caltech) Alice Shapley (Michigan) Michael Murphy (IoA( IoA)
Mg II Absorption Studies 1) Spectroscopic Surveys 2) Connection to Galaxies Spectroscopic UV (z<0.1) Churchill (2001) OPTICAL (0.1<z<2.2) Lanzetta+ (1987, LTW) Tytler+ (1987) Steidel+ (1988, SBS88) Caulet (1989) Petitjean & Bergeron (1990, PB90) Boisse + (1992) Steidel & Sargent (1992, SS92) Churchill+ (1999) Churchill & Vogt (2001) Churchill+ (2003) Nestor+ (2005) Procter+ (2005) IR (2.2<z<4.5) Elston+ (1994) Kobayashi+ (in prep, IRCS/Subaru) Connection to Galaxies ESTABLISHMENT Yanny & York (1990) Lanzetta & Bowen (1990) Bergeron & Biosse (1991, BB91) Steidel+ (1994, SDP94) Bowen+ (1995, BBP94) Steidel (1995, S95) Guillemin & Bergeron (1997) Rao & Turnshek (1999) GAS KINEMATICS Lanzetta & Bowen (1992) Churchill+ (1996,CSV96) Churchill+ (2000a,b) GALAXY MORPHOLOGES Steidel+ (1997) Kacprzak+ (talk today) GAS/GALAXY KINEMATICS Steidel+ (2002) Ellison+ (2003) Multiphase Ionization and Kinematics Ding+ (2003) Charlton+ (2003) Zonak+ (2004) Ding+ (2005)
Mg II Absorption Selects DLAs: N(HI)>2x10 20 cm -2 (eg. Le Brun+ 1997; Rao & Turnshek 2000; Churchill+ 2000) 0.1 L * galaxies and LSB galaxies Wide range of galaxy morphologies Mg II: black-bottom profiles; Dv~200 km s -1 C IV: average absorption strengths If you observe
Mg II Selects Galactic Environments DLAs: N(HI)>2x10 20 cm -2 (eg. Le Brun+ 1997; Rao & Turnshek 2000; Churchill+ 2000) 0.1 L * galaxies and LSB galaxies Wide range of galaxy morphologies Mg II: black-bottom profiles; Dv~200 km s -1 C IV: average absorption strengths LLSs: N(HI)>2x10 17 cm -2 (eg. Steidel et al 1994; Churchill+ 1996; Churchill & Vogt 2001) Normal, bright galaxies; L>0.1L*-3L* Mg II: complex kinematics; Dv~100-400 km s -1 ; C f ~1 Mg II: Weak narrow high vel components C IV: absorption strengths vary C IV: correlates with Mg II kinematic spread If you observe
Mg II Selects Galactic Environments DLAs: N(HI)>2x10 20 cm -2 (eg. Le Brun+ 1997; Rao & Turnshek 2000; Churchill+ 2000) 0.1 L * galaxies and LSB galaxies Wide range of galaxy morphologies Mg II: black-bottom profiles; Dv~200 km s -1 C IV: average absorption strengths LLSs: N(HI)>2x10 17 cm -2 (eg. Steidel et al 1994; Churchill+ 1996; Churchill & Vogt 2001) Normal, bright galaxies; L>0.1L*-3L* Mg II: complex kinematics; Dv~100-400 km s -1 ; C f ~1 Mg II: Weak narrow high vel components C IV: absorption strengths vary C IV: correlates with Mg II kinematic spread sub-llss: N(HI)<6x10 16 cm -2 (eg. Churchill+ 1999 ; Churchill & Charlton 1999; Rigby + 2001) Normal bright galaxies (some), dwarf galaxies? Mg II: cloud sizes ~10 pc to ~10 kpc Z>0.1 solar; 0<[a/Fe]<+0.5; C f ~0.15? C IV: range of absorption strengths many multiphase ionization If you observe ranging over five decades of N(HI)
What Galaxy Types are Selected by Mg II Absorbers? Population of normal morphology, bright galaxies are selected by Mg II absorbing gas cross section Steidel (1998); Kacprzak+ (2005) Little to no evolution in luminosity function except for a paucity of faint blue galaxies Steidel+ (1994) F= F*(L/L*) -a exp(-l/l*) h 3 Mpc -3 F*=0.03 h 3 Mpc -3 a=-1
Mg II Absorption Cross Sections Statistical sizes based upon Redshift Path Densities.. Sargent, Steidel, & Boksenberg 1988 Steidel & Sargent 1992 Steidel 1993 HST KP 1995 Churchill 2001 Churchill & Vogt 2001 Nestor+ 2005 dn/dz = D H ns(1+z) 2 H 0 /H(z) ns = F(L)pR(L) 2 (integrated) F(L) = 0.03(L/L*) -1 exp(-l/l*) h 3 Mpc -3 R(L) = R*(L/L*) -b h -1 kpc
Mg II Absorption Cross Sections Statistical sizes based upon Redshift Path Densities.. Sargent, Steidel, & Boksenberg 1988 Steidel & Sargent 1992 Steidel 1993 HST KP 1995 Churchill 2001 Churchill & Vogt 2001 Nestor+ 2005 DLA: 6h -1 kpc LSB included F*=0.08 h 3 Mpc -3 DLA: 15h -1 kpc LSB excluded F*=0.03 h 3 Mpc -3 40h -1 kpc Mg II: W(2796)>0.3 A LLS : F*=0.03 h 3 Mpc -3 Mg II: C IV : 70h -1 kpc W(2796)<0.3 A W(1548)>0.3 A
Is There a Halo Size - Mass/Luminosity Relationship? Does the Gas Follow a Smooth Radial Dependence? The R(L) Relation Minimize number of nonabsorbers below the line Minimize number of absorbers above the line R = R*(L/L*) -b b=0.15 R* = 40h -1 kpc Steidel (1995) Spherical; C f =1
Does the Gas Follow a Smooth Radial Dependence? The 3.1 s anti-correlation between equivalent width and impact parameter. Halos are patchy (as seen in the scatter), but appear to obey overall trend Is there a maximum equivalent width at each impact parameter? Steidel (1995) EW is strongly dependent upon the velocity spread and number of clouds intercepted by the quasar sightline, so the scatter speaks to the velocity spreads variations or additional parameters
Mg II Kinematics Galaxy Morphology Connection Building a sample comprising - High resolution quasar spectra HIRES / Keck UVES / VLT STIS / HST - High spatial resolution images WFPC-2 / HST - Spectroscopic galaxy redshifts Lick, Keck, APO We have so far obtained 37 Mg II absorption selected galaxies See talk tomorrow: Glenn Kacprzak (NMSU)
Sample: Equivalent Width vs. Impact Parameter.3
Sample: Equivalent Width vs. Impact Parameter.3 Weak Mg II W(2796)<0.3 A used to be called non-absorbers
Sample: Equivalent Width vs. Impact Parameter.3 predicted to not give rise to absorption
WFPC-2/HST Images 5 x5 stamps HIRES/Keck Spectra R=45,000 r-f velocity UVES/VLT Spectra R=44,000 r-f velocity R* for L* galaxies W(2796) > 0.3 A
PANEL 1. D<30 h -1 kpc QSO QSO aligned downward
PANEL 2. 30<D<60 h -1 kpc
PANEL 3. D>60 h -1 kpc
A Few Case Studies SDP Galaxy sample/survey incomplete 70% spectroscopic redshifts 30% remain candidates search pattern biased toward most likely galaxy (nearest quasar), stopped after confirmation General Picture is essentially correct, but there is much to be learned in detail in patch-work follow-up studies, several absorber hosts found to be - misidentified - unidentified - double galaxies or ambiguous identity What are Implications?
The Q0002+051 Field 0.2981 41.7
The Q0002+051 Field 0.2981 41.7 0.5915 25.5 z=0.2981
The Q0002+051 Field 0.8514 18.2 0.2981 41.7 0.5915 25.5 z=0.2981 z=0.5915
The Q0002+051 Field 0.8514 18.2 0.2981 41.7 0.5915 25.5 0.8665? z=0.2981 z=0.5915 z=0.8514
The Q0002+051 Field 0.8514 18.2 0.2981 41.7 0.5915 25.5 0.9560? z=0.2981 z=0.5915 z=0.8514 z=0.8665
The Q0002+051 Field G3 0.8514 18.2 G4 G5 G1 0.2981 41.7 Galaxies at z=0.8665 & 0.9560? Candidate D h -1 G1 63 G2 50 G3 54 G4 58 G5 70 z=0.9560 G2 0.5915 25.5 z=0.2981 z=0.5915 z=0.8514 z=0.8665
The Q1222+228 Field z=0.5502 G1 G2 G6 G5 0.5502 25.6h -1 kpc 0.091 A G3 z=0.6681 G4 Galaxy at z=0.6681? Candidate D h -1 Candidate D h -1 G1 69 G4 97 G2 83 G5 108 G3 63 G6 86
The Q1317+174 Field Z=? D=? <~0.01 A 0.6720 40.9h -1 kpc <0.006 A z=0.6610 0.6610 72.3h -1 kpc 0.34 A z=0.6720 z=0.6610 absorption significantly beyond expected 40h -1 kpc impact parameter z=0.6720 a true non-absorbing galaxy Small D galaxy with no abs (in covered l )
Galaxies Selected by Weak Mg II Absorption QSO aligned downward QSO L~0.3-0.6L*
Weak Absorption appears to select moderate luminosity galaxies at a wide range of impact parameter they have just been overlooked Impact Parameters of Weak System Galaxies
Mg II Weak Absorption Studies Statistical population study presently extends from 0.4<z<1.4?
Mg II Weak Absorption Survey at z>1.4 w/ Wal Sargent, Michael Rauch, & Michael Murphy 108 HIRES/Keck spectra 81 UVES/VLT spectra Have analyzed only 78 HIRES Spectra so far. At higher redshift, the critical calculation is the redshift path of the survey sky lines, blends, and heavy atmospheric absorption requires careful accounting So far, we find
Mg II Weak Absorption Survey at z>1.4 With additional 100 spectra, most with redder wavelength coverage, we anticipate a factor of two decrease in the error bars dn/dz = 1.3+/- 0.4 (1.50<z<2.30) dn/dz = 1.6+/- 0.7 (1.50<z<1.54) dn/dz = 1.0+/- 0.5 (1.55<z<2.30) See Poster: Misawa etal
QSO z-space Density Space density of quasars drops 0.7 dex from z=2.2 to z=1.4 It drops a further 2 dex by z=1.0! Weak Mg II z-path Density
QSO z-space Density Space density of ionizing photons drops 0.5 dex from z=2.2 to z=1.4, and continues to drop rapidly with decreasing redsdhift. l 912 z-space Density Weak Mg II z-path Density
QSO z-space Density Lya z-path Density l 912 z-space Density Weak Mg II z-path Density
Concluding Remarks Extended gaseous regions surrounding intermediate redshift galaxies are more patchy than previously reported, but a complete and unbiased survey of the quasar fields is required to document the details
Concluding Remarks Extended gaseous regions surrounding intermediate redshift galaxies are more patchy than previously reported, but a complete and unbiased survey of the quasar fields is required to document the details We are making our first strides toward quantifying the galaxy morphologies and sightline orientations and comparing with the gas kinematics; the 10-fold increase in spectroscopic sensitivity is key
Concluding Remarks Extended gaseous regions surrounding intermediate redshift galaxies are more patchy than previously reported, but a complete and unbiased survey of the quasar fields is required to document the details We are making our first strides toward quantifying the galaxy morphologies and sightline orientations and comparing with the gas kinematics; the 10-fold increase in spectroscopic sensitivity is key Normal, non-dwarf galaxies are associated with a substantial number of the weak Mg II population, likely at full range of impact parameters
Concluding Remarks Extended gaseous regions surrounding intermediate redshift galaxies are more patchy than previously reported, but a complete and unbiased survey of the quasar fields is required to document the details We are making our first strides toward quantifying the galaxy morphologies and sightline orientations and comparing with the gas kinematics; the 10-fold increase in spectroscopic sensitivity is key Normal, non-dwarf galaxies are associated with a substantial number of the weak Mg II population, likely at full range of impact parameters The number density of weak Mg II absorbers increases with cosmic time from redshifts z=2.2 to z=1.5, and then is consistent with no evolution for z<1.5, probably heavily influenced by evolution in UV ionizing background
Concluding Remarks Extended gaseous regions surrounding intermediate redshift galaxies are more patchy than previously reported, but a complete and unbiased survey of the quasar fields is required to document the details We are making our first strides toward quantifying the galaxy morphologies and sightline orientations and comparing with the gas kinematics; the 10-fold increase in spectroscopic sensitivity is key Normal, non-dwarf galaxies are associated with a substantial number of the weak Mg II population, likely at full range of impact parameters The number density of weak Mg II absorbers increases with cosmic time from redshifts z=2.2 to z=1.5, and then is consistent with no evolution for z<1.5, probably heavily influenced by evolution in UV ionizing background Stay tuned